Effect of Silver Nitrate and Thidiazuron on Shoot Proliferation, Hyperhydricity and Assessment of Genetic Fidelity of Microplants in Carnation (Dianthus caryophyllus L.)

In the present investigation, optimization of the best concentration combinations of BAP (Benzyl Amino Purine), TDZ (Thidiazuron) and Silver Nitrate (AgNO3) for micropropagation of carnation (Dianthus caryophyllus L.) cv. Irene was performed. Genetic fidelity in the microplants of different generation was determined with the help of ISSR markers. Results of the present investigation showed that the MS gelled media supplemented with BAP (0.5 mg L-1) and AgNO3 (1.5 mg L-1) showed maximum shoot proliferation, good shoot length and reduced hyperhydricity significantly. Our study also indicates that hyperhydricity decreased by substantially by increasing the concentration of AgNO3 compared to control. High level of AgNO3 in MS medium did not helped to reduce hyperhydricity. Another chemical combination of TDZ (1.0 mg L-1) and AgNO3 (0.5 mg L-1) in MS gelled media gave the maximum shoot proliferation, shoot length with minimum hyperhydricity which showed normal growth and development compared to control and other treatments. This concentration combination proved effective to reduce hyperhydricity and to enhance shoot proliferation. Because TDZ with AgNO3 had pronounced effect to reduce hyperhydricity, therefore, this concentration combination was used to advance the progeny up to subculture (SC10) using donor mother microplants (SC1) selected from the best concentration response to know the genetic fidelity among the different generations. Microplants which were non hyperhydrified were used to assess the genetic fidelity using ISSR markers. Fourteen ISSR primers were used that gave good amplification and produced 616 bands with an average of 44 amplicon per primer from in vitro raised microplants including mother plant where the banding patterns exhibited uniform and homogeneous banding patterns. This study may help us to know applicability of ISSR markers to establish genetic fidelity among in vitro-raised microplants of carnation.